This invention relates generally to mechanical air sample collectors used to detect the presence of airborne impurities in ambient air and, more particularly, but not by way of limitation, to volumetric air samplers that collect multiple discrete samples periodically, over set periods of time, without supervision.
Air sampling to determine the contents of an airborne environment is important to determine if microscopic objects of medical and/or biological interest, both vegetable and mineral, are present in the air in a given location. Among objects to be collected, most important are airborne pollens, fungal spores and other objects of interest to allergists, other physicians, botanists and plant pathologists. Furthermore, for various purposes which will become apparent in the following disclosure, it is important to determine at what periods of the day such objects are released into the air.
A conventional air sampling device can only collect one large sample over its normal sampling period. Although the sampling period can be varied in length, only one sample can be obtained. One such machine takes a sample for one minute out of every ten minutes in a 24-hour period, which produces a cumulative sample composed of 144 smaller samples laid down one on top of the other. As there is no way to know at what time any of these objects were collected, the volumetric count is simply an averaged count expressed as a number per cubic meter for each of the objects collected.
Samples collected by the above method are laid down on top of each other and, thus, periods of high object counts followed by an extended period of little or no release of objects from trees and fungi causes the larger number collections to be diluted and averaged along with smaller or zero counts from subsequent and previous sampling periods. The resulting average number does not reflect an accurate picture of what precisely happened in the test environment during the 24-hour period. The times of the day when counts that were high enough to produce pronounced allergic symptoms in sensitive persons, or which threatened the health of particular plants, cannot be isolated.
Another currently available device takes single samples every hour on conventional reading devices such as normal laboratory slides. However, this machine is limited by the fact that the operator using it must time the sampling period hourly and constantly reset the machine "on" and "off" every hour. This allows collection of only one sample every hour and must be constantly and tediously attended to by an operator.
Another available device takes a continuous sample on sticky tape attached to a rotating drum. The sampling period can be one to seven days, depending upon the setting of the machine. The resulting samples collected with this machine, again, reflect only an average volumetric count for the period, which makes it impossible to determine at what specific time of day the high concentration of the objects were released into the test environment. Furthermore, preparing the sticky tape for microscopic examination to determine the number of objects collected can present serious problems if the operator lacks the necessary dexterity and training.
Trees, weeds, grasses and other plants that produce pollen and fungi that produce spores do not release same continuously, and some do so only for short periods of time. Each variety may only release once each day at quite different times during a 24-hour period. Although some release randomly throughout the day, others are more consistent in their behavior. Some trees release pollen only during daylight hours, while others may do so during the hours of darkness. The same is equally true of other plants and various fungi. For this reason, random sampling or taking of only a few arbitrary samples each day may completely miss a high pollen or mold count.
It is useful to know at what times of the day various plants and fungi released large quantities of pollen or spores so that they may be related to the allergic symptoms of those whose reactions began at about the same time of day. The frequency with which this invention is able to take discrete samples, identifiable as to time, makes detection of such surges almost certain. This information is useful in providing treatment for patients whose allergies are known and may provide important clues as to the allergens affecting patients whose allergies have not been identified.
The present invention overcomes the shortcomings of the prior art by providing a volumetric air sampler that can collect multiple discrete samples of microscopic objects over set periods of time with minimal supervision at frequencies determined and programmed electronically by an operator.
The present invention allows volumetric counts of objects at given time periods. This, in turn, is a good reflection of the air concentration of these objects at that particular time. Since the volume of air sampled at a given and discrete period is known, the count is easily converted to the number contained in a cubic meter or other volumetric measure of air. High counts are associated with various human, animal and plant allergies and associated diseases, while low counts are considered with less significance.
Taking multiple discrete samples has not been possible until the present invention because no means existed for moving a laboratory slide in precise increments and in a precise relationship with an air source. There is a need for an apparatus by which a laboratory slide can be moved precise increments, combined with an accurate timing device which provides multiple discrete samples identifiable as to the day and time at which they were collected.
The present invention provides these unique advantages that were not available in the relevant market prior to this disclosure. These and other novel advances provided by this disclosure will be apparent to those skilled in the art in the following Summary of the Invention.